Lithium batteries have been extensively used as a reliable source of electrical energy. However, at the end of the useful life of these batteries there is a need for the safe dismantling, destruction and disposal or recycling of the components of lithium batteries because of the hazardous nature of the components and the reaction products generated in discharge and destruction of these batteries. With the advent of electrical vehicles and EPA regulations restricting further the emissions allowable from vehicles and disposal sites, it is likely that such high energy batteries, or batteries of different composition with similar disposal problems will be used in greatly increased quantities.
The disposal of lithium batteries can be extremely dangerous because the cell components as well as the products created on discharge of the cells are unstable and the battery destruction process can result in explosive reactions, fires and the release of corrosive and toxic byproducts. Exposure of thionyl chloride to water rapidly creates hydrochloric and sulfuric acid forming a toxic cloud of acid which can include entrained thionyl chloride. Batteries composed of lithium bromide and sulfur dioxide dissolved in acetonitrile produce toxic cyanides upon discharge. Elemental lithium exposed to water can decompose the water to release hydrogen which forms an explosive mixture with oxygen. In particular, the prior technique for disposal of lithium cells disclosed in U.S. Pat. No. 4,637,928 can result in the release of toxic gases formed during reactions to neutralize the battery components. The technique disclosed therein incorporates a hammermill into which lithium batteries are fed in their "as received" form, i.e. not discharged, dismantled or disassembled.
The hammermill is located in an explosion proof room specifically designed to retain the toxic off gases which occur during the battery destruction process. The hammers impacting on the sealed batteries cause an explosive release of energy. The water used to immerse the exposed components causes the lithium to react explosively and hydrogen gas to be released which also could explosively combine with reactants. The thionyl chloride and hydrogen can also react to form a toxic mist of hydrochloric and sulfuric acid and thionyl chloride which fills the room housing the hammermill.
The present invention is primarily designed for the disposal of batteries with cells composed of a lithium metal anode and a liquid thionyl chloride electrolyte. However, it is also applicable to other battery compositions based on lithium, such as lithium/sulfur dioxide, lithium/sulfuryl chloride, lithium/iodine, lithium/iron disulfide, lithium/polymer, lithium/magnesium dioxide or lithium/carbon monofluoride batteries, or batteries utilizing other hazardous anode, cathode and electrolyte combinations such as nickel/metal hydride or sodium/sulfur sodium/nickel batteries.
Accordingly, there is a need for a process which will allow the safe and controlled dismantling and destruction of used lithium cells which avoids the release of toxic materials, reduces the chance of explosion and fire during disposal and places the materials generated in the destruction process in a suitable form for disposal or recycling.